A method and device for determining pancreatic lipase in an animal blood sample. In one aspect, the device includes a compartmentalized container for storing and reacting the reagents for use in the assay. In another aspect, the device include a multilayer device having a spreading layer and reagents layers with dried reagents for detecting pancreatic lipase. The devices also includes a system for the optical determination of a color change in the reaction mixture. The method includes the use of the device to detect pancreatic lipase in samples.